How to add `spring` to your rails plugin / engine for use with RSpec and beyond.

Gemfile

# In `your_engine/Gemfile` add the pertinent spring gems:
# Note, do not add spring gems as `spec.add_development_dependency`'s in your gemspec. 
source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

gemspec

group :development do
  gem 'spring'
  gem 'spring-watcher-listen'
end

# If you're using rspec:
group :test do
  gem 'spring-commands-rspec'
end

spring.rb

# Add `spring.rb` to your engine's config folder:
# `your_engine/config/spring.rb`
#
# when generating a plugin via `rails plugin new your_engine`
# (without customizing the dummy_app path)
# a dummy rails app is created.
#
# If you're using RSpec, you'll path will look like: './spec/dummy'

Spring.application_root = './test/dummy'

Using spring binstubs in the terminal

Remember to re-bundle your gem from the gem's root directory once you've made these changes. The root Gemfile will automatically be applied to the dummy app.

When using RSpec, you can spring your tests via:

$ spring rspec spec/features/my_feature_spec.rb

Or, in entirety:

$ spring rspec

---

How to generate your plugin so it's ready for RSpec

You can also utilize RSpec's spec/ folder for placement of your dummy app by adding the following flags to your generation:

• --skip-test
• --skip-system-test
• --dummy-path=spec/dummy

Example:

$ rails plugin new your_plugin_name --skip-test --skip-system-test --dummy-path=spec/dummy

Then, you simply add rspec-rails as a development dependency, re-bundle, then run the RSpec installation generator:

# in your_engine.gemspec
...
Gem::Specification.new do |spec|
  ...
  spec.add_development_dependency 'rspec-rails'
end

$ rails generate rspec:install

Good to go!